username="zs"
password="ls"
i=0
while i <= 3:
    username=input("请输入您的账号 ")
    password=input("请输入您的密码 ")
    if not username or username != "zs" or password != "ls":
        print("用户名或密码错误")
        i+=1
    else:
        print("登录成功")
        break
# print("用户名或密码错误") if not username or else print("等了成功")
   # 来个错误次数提示？